Method and apparatus for forming alternate reverse twists in a strand



Sept. 24, 1968 w. R. MICHAEL ET AL 3,402,544-

METHOD AND APPARATUS FOR FORMING ALTERNATE REVERSE TWISTS IN A STRAND 3 Sheets-Sheet 1 Filed June 26, 1967 INVENTOES .RMICHAEL. O.H.OL.SON I D.E.EESEE MW ATTORNEY Sept. 24, 1968 w. R. MICHAEL ET AL 3,402,544

METHOD AND APPARATUS FOR FORMING ALTERNATE REVERSE TWISTS IN A STRAND Filed June 26, 1967 3 Sheets-Sheet 2 a E J a Sept. 24, 1968 Y w.

METHOD AND APPARATUS FOR FORMING ALTERNATE REVERSE TWISTS IN 'A STRAND Filed June 26. 1967 3 Sheets-Sheet 5 95 1: 97 lavv -..l6

' 'EQSC-I I3 27 L MOTOR sac-4 I I r n 74 l l I 99 IOI COUNTER United States Patent 3,402,544 METHOD AND APPARATUS FOR FORM- ING ALTERNATE REVERSE TWISTS IN A STRAND William R. Michael, Millard, and Orvin H. Olson and Donald E. Rcser, Omaha, Nebn, assignors to Western Electric Company, Incorporated, New York, N.Y., a corporation of New York Filed June 26, 1967, Ser. No. 648,672 Claims. (Cl. 57-34) ABSTRACT OF THE DISCLOSURE The forming of reverse twists in a strand involves alternately advancing the strand longitudinally relative to a pair of spaced strand engaging mechanisms and a continuously rotating intermediate strand engaging mechanism, and alternately precluding strand advancement relative to the several strand engaging mechanisms while the rotating intermediate strand engaging mechanism imparts reverse twists to the portions of the strand extending between the intermediate strand engaging mechanism and the spaced strand engaging mechanisms.

Background of the invention (1) Field of the invention.This invention relates to the forming of alternate reverse twists in a strand and more particularly to the twisting of two insulated electrical conductor wires together to form a twisted wire pair.

In the manufacture of communication cable it is standard practice to intertwist a pair of longitudinally advancing insulated wires to form a twisted wire pair. A plurality of the twisted pairs, each having a twist of a different pitch for the purpose of eliminating crosstalk in the \finished cable, subsequently are fed into a cable strander which gathers the twisted pairs into groups and binds each group into a cable core sub-unit. The cable strander then gathers the bound cable core subunits and binds them together to form a cable core.

(2) Description of the prior art.The interwisting of the insulated wires to form a twisted wire pair may be accomplished by a process in which the wires are twisted together continuously to form a unidirectional twist therein, and in which it is necessary to rotate either the wire supply or the wire takeup about the longitudinal axis of the wires in the forming of the unidirectional twist in the wires. It also may be accomplished by a process in which alternate reverse twists, that is, alternate twists of opposite hand, are imparted to the wires.

Each type of process possesses certain advantages over the other, with the alternate reverse twisting type of process being advantageous from the standpoint of not having to rotate either the wire supply or the wire takeup about the longitudinal axis of the wires. In this connection, in the alternate reverse twisting type of process the insulating, twisting and stranding operations on the wires can be performed in tandem instead of separate ly with intermediate rotating wire takeups and supplies, as in the unidirectional twisting type of process. Further, where intermediate wire supplies and takeups are used in an alternate reverse twisting operation, since they can be of a nonrotating type they can have a greater wire capacity than the rotating reel type of wire supplies and takeups normally used in a unidirectional twisting operation.

:In known apparatus for forming alternate reverse twists in a pair of longitudinally advancing wires, a twist imparting mechanism grips the advancing wires at longitudinally spaced points and then advances with the wires a preselected distance. During the advancement of the Patented Sept. 24, 1968 twist imparting mechanism with the wires it causes relative rotation between alternate ones of the gripped points to impart twists of opposite hand to the wires. Upon reaching the end of its advancing movement the twist imparting mechanism releases the wires and is returned to a starting position where it grips a next succeeding increment of the wires at longitudinally spaced points and the twist imparting operation is repeated. During the return movement of the twist imparting mechanism in certain known apparatus, the advancement of the wires may be temporarily stopped, it so desired.

Summary of the invention An object of the invention is to provide a new and improved method and apparatus for forming alternate reverse twists in a strand.

In accordance with the invention, in the forming of alternate reverse twists in a strand, the strand is intermittently advanced longitudinally so as to move at least two sections of the strand into strand twisting position with each advancement of the strand. When each two sections of the strand are in strand twisting position, longitudinal advancement of the part of the strand between outer limits of the two sections of the strand is precluded and relative rotation is caused between a portion of the strand intermediate the two sections of the strand and portions of the strand at the outer limits of the two sections of the strand, to form reverse twists in the two sections of the strand.

More specifically, continuous relative rotation is caused between a strand engaging mechanism and strand support points spaced from the strand engaging mechanism longitudinally of the strand on respective opposite sides of the strand engaging mechanism. Alternate reverse twists then are formed in the strand by intermittently advancing the strand longitudinally relative to the strand support points and the strand engaging mechanism, so as to move at least two sections of the strand into strand twisting position between the strand engaging mechanism and respective ones of the strand support points with each advancement of the strand, and by precluding the advancement of the part of the strand intermediate the strand are in strand twisting position, so that desired reverse twists are formed in the sections of the strand by the relative rotation between the strand support points and the strand engaging mechanim.

In specific apparatus in accordance with the invention, the strand engaging mechanism defines a strand storing position having a capacity of two unit lengths of the strand, and each strand support point is located one unit length from the thus defined strand storing position. The strand passes about a first guide member of a reciprocable means prior to passing to a first one of the strand support points and into the strand storing position, and passes about a second guide member of the reciprocable means after passing from the strand storing position and a second one of the strand support points. The reciprocable means and the guide members thereof are moved in one direction at a rate of speed corresponding to the strand advancing speed of a constant speed strand advancing means so that the part of the strand intermediate the strand support points remains stationary and desired reverse twists are formed in the unit length sections of the strand between the strand support points and the strand storing position by the relative rotation therebetween, and are moved in the reverse direction to advance the portion of the strand intermediate the strand support points two unit lengths.

Brief description of the drawing FIG. 1 is a side elevational 'view of apparatus in accordance with the invention, partially in cross section;

FIG. 2 is an isometric, schematic diagram of a hydrau lic control system for the apparatus shown in FIG. 1; and

FIG. 3 is a schematic diagram of an electrical control system for the apparatus shown in FIG. 1.

Detailed description Referring to FIG. 1, it is seen that the illustrated em bodiment of the invention is designed to provide alternate reverse twists in a strand 11 in the form of a pair of insulated electrical conductor wires. In the disclosed apparatus the insulated wires 11 are advanced from left to right, as viewed in FIG. 1, from a suitable source of supply (not shown) and through the apparatus by a capstan 12 driven by an adjustable speed electric motor 13. Subsequently, the twisted wires 11 pass from the power driven capstan 12 to the right in FIG. 1 to a suitable takeup (not shown). The source of supply and the takeup preferably are of a nonrotatable type which have a capacity of a substantial length of the wires 11, and the source of supply may be two adjacent wire insulating lines while the takeup may form a part of a cable strander.

The apparatus includes a rotatable flyer 14 which includes a suitable rectangular framework 16 and sets of wire guide sheaves 17, 18 and 19, 21 rotatably mounted in brackets 22 fixedly secured to the framework in diagonally opposed corners thereof. The flyer 14 is mounted for rotation about the longitudinal axis of the rectangular framework 16 in a main frame 23 by trunnions 24 secured to the framework and journalled in suitable bearings 26 in horizontally spaced uprights of the main frame. The flyer 14 is rotated in the direction indicated by the arrow in FIG. 1 by an adjustable speed electric motor 27 on the main frame 23, through a belt and pulley drive which includes a pulley 28 keyed or otherwise suitably secured to one of the trunnions 24. The trunnions 24 are provided with axial bores for permitting the pair of insulated wires 11 to pass therethrough. Since the maximum possible rotational speed of the flyer 14 (and thus the twisting speed of the apparatus) is dependent on its rotational inertia, the rotational inertia of the flyer should be kept as low as possible.

The set of wire guide sheaves 17 and 18 adjacent the entrance or left hand end of the fiyer 14, as viewed in FIG. 1, are mounted in the flyer so that a wire support point 17a at which the pair of insulated wires 11 initially engages the sheave 17 is located substantially on the axis of rotation of the flyer, with the sheave 18 being spaced from the fiyers axis of rotation. Similarly, the set of sheaves 19 and 21 adjacent the exit or right hand end of the flyer 14, as viewed in FIG. 1, are mounted in the fiyer so that a wire support point 19a at which the pair of insulated Wires 11 leaves the sheave 19 is located substantially on the axis of rotation of the flyer, with the sheave 21 being spaced from the flyers axis of rotation. Thus, as the flyer 14 rotates, the portion of the pair of insulated wires 11 between the wire support points 17a and 19a rotates therewith.

Adjacent the entrance to the flyer 14 a wire guide sheave 29 is mounted externally of the flyer, and adjacent the exit from the flyer another wire guide sheave 31 is mounted externally of the flyer. The sheaves 29 and 31 are mounted on outer end portions of respective laterally projecting supports 32 having their inner ends secured to respective uprights of the main frame 23, so that a wire support point 29a at which the pair of insulated wires 11 leaves the sheave 29 and a wire support point 31a at which the pair of insulated wires initially engages the sheave 31 are located substantially on the axis of rotation of the flyer 14. The distance between the point 29a on the sheave 29 and the point 17a on the sheave 17 inside the flyer 14, and the distance between the point 31a on the sheave 31 and the point 1911 on the sheave 19 inside the flyer, are equal to one unit length of the pair of insulated wires 11. The

distance between the points 17a and 19a on the sheaves 17 and 19, as measured along the path of travel of the wires through the flyer, is equal to two unit lengths of the pair of insulated wires 11, whereby the flyer has a wire storing capacity of two unit lengths for reasons which subsequently will become apparent.

The pair of insulated wires 11 passes from the abovementioned source of supply through a suitable accumulator 33, which in the illustrated embodiment of the invention includes entrance and exit sheaves 34 and 36, respectively, a plurality of coaxial sheaves 37 having a fixed axis of rotation, and a plurality of coaxial dancer sheaves 38, the wires traveling back and forth about the sheaves 37 and 38 in a well known manner. The sheaves 37 are mounted between upper end portions of horizontally spaced vertical frame members 39 (only one shown), while the sheaves 38 are suitably mounted for vertical movement between the vertical frame members and biased downward by counterweights (not shown). The pair of insulated wires 11 passes from the accumulator 33 and about a guide sheave 41 rotatably mounted on a reciprocating carriage 42, then over a guide sheave 43 rotatably mounted in a bracket secured to the adjacent upright of the main frame 23, and then to the sheave 29.

Similarly, the pair of insulated wires 11, after the alternate reverse twists have been formed therein, passes from the sheave 31 adjacent the exit end of the flyer 14 and about a guide sheave 44 rotatably mounted in a bracket secured to the adjacent upright of the main frame 23. The twisted pair of insulated wires 11 then passes about a guide sheave 46 rotatably mounted on the reciprocating carriage 42, through an accumulator 47, and then about the wire advancing capstan 12 to the above-mentioned takeup. The accumulator 47 is of the same construction as the accumulator 33 and includes a plurality of coaxial sheaves 48 having a fixed axis of rotation, and a plurality of counterweighted, coaxial dancer sheaves 49, the sheaves 48 and 49 being mounted between vertical frame members 51 (only one shown).

The carriage 42 is mounted for horizontal reciprocable movement between solid line and dashed line positions, as illustrated in FIG. 1, on horizontally spaced guide rods 52 having their opposite ends secured to the uprights of the main frame 23. The carriage 42 is reciprocated by a double acting hydraulic cylinder 53 having outer ends of piston rods 54 thereof connected to the carriage by roller type chains 56 which travel about respective peripherally grooved guide rollers 57. The guide rollers 57 are rotatably mounted in upstanding supports 58 located beneath support stands 59 for the accumulators 33 and 47.

In a wire twisting phase of the machines operating cycle, the hydraulic cylinder 53 moves the carriage 42 to the right in FIG. 1, from its solid line position to its dashed line position, at a speed corresponding to the speed of advancement of the pair of insulated wires 11 by the capstan 12, whereby the part of the pair of insulated wires between the wire support points 29a and 31a on the sheaves 29 and 31, remains stationary. Thus, twists of opposite hand are formed in the pair of insulated wires 11 between the points 17a and 29a on the sheaves 17 and 29 and the points 19a and 31a on the sheaves 19 and 31.

During this movement of the carriage 42 the dancer sheaves 38 of the accumulator 33 preclude excessive tension in the pair of insulated wires 11 by moving vertically in response to an increase or decrease in tension in a well known manner. Further, where the rate of feed of the pair of isulated wires 11 from the above-mentioned source of supply is substantially constant, as for example where the source of supply is two adjacent wire insulating lines, the dancer sheaves 38 move upward to pay out two unit lengths of the pair of insulated wires to the carriage sheave 41 to permit this movement of the carriage 42 to take place. At the same time a two unit length slack being created in the twisted pair of insulated wires 11 by the movement of the carriage sheave 46, is taken up by downward vertical movement of the dancer sheaves 49 of the accumulator 47.

During the forming of the twists in the unit lengths of the pair of insulated wires 11 the wire guide sheaves 29, 31, 43 and 44 are locked against rotation by associated electric brakes 61 of any suitable type, to help preclude inadvertent longitudinal movement of the portion of the pair of insulated wires between the carriage sheaves 41 and 46. For example, in the illustrated embodiment of the invention, each brake 61 includes a cylindrical drum member 62 suitably secured to its associated one of the sheaves 29, 31, 43 or 44 for rotation therewith. Each brake 61 also includes a brake shoe 63 which is biased to a released position in a suitable manner (not shown) and which is movable into engagement with its associated drum member 62 upon energization of an associated electrical winding 64 (FIG. 3). In the alternative, the brake shoes 63 could be constructed in the form of clamp members engageable directly with the wires 11 and the peripheries of the sheaves 29, 31, 43 and 44, with the clamp members engaging the sheaves 29 and 31 at the points 29:: and 31a, respectively, to help insure against twisting rotation of the wires 11 at these points. Housings 66 of the electric brakes 61 associated with the sheaves 29 and 31 are mounted on the laterally projecting supports 32 for these sheaves, and housings 66 of the electric brakes associated with the sheaves 43 and 44 are mounted on respective ones of the uprights of the main frame 23 by suitable brackets.

As the carriage 42 is moved from its dashed line position back to its solid line position in FIG. 1 by the hydraulic cylinder 53, in a wire advancing phase of the machines operating cycle, the part of the pair of insulated wires 11 between the carriage sheaves 41 and 46 is pulled through the apparatus two unit lengths. More specifically, this movement of the carriage 42 moves an untwisted unit length of the pair of insulated wires 11 into position between the wire support points 17a and 29a adjacent the entrance to the flyer 14, (1) an untwisted unit length of the wires and (2) the twisted unit length of the wires between the wire support points 17a and 2911, into the flyer between the wire support points 17a and 19a, an untwisted unit length of the wires from the flyer into position between the wire support points 19a and 31a adjacent the exit from the flyer, and (1) a previously twisted unit length of the wires from the flyer and (2) the twisted unit length of the wires between the wire support points 19a and 31a, into a position about and beyond the wire guide sheave 31 toward the carriage.

In this connection, when the carriage 42 is in its dashed line position in FIG. 1 the twisted pair of insulated wires 11 initially engages the guide sheave 46 on the carriage at a point 46a and leaves the guide sheave at a point 46b. The travel of the carriage 42 is such that when it is in its solid line position shown in FIG. 1 the distance between the two points 46a and 46b, as measured along the twisted pair of insulated wires 11 and about the guide sheave 46, is equal to two unit lengths of the twisted wires. Similarly, when the carriage 42 is in its solid line position in FIG. 1 the pair of insulated wires 11 initially engages the guide sheave 41 on the carriage at a point 41a and leaves the guide sheave at a point 41b, with the distance between these points when the carriage is in its dashed line position, as measured along the pair of insulated wires and about the guide sheave 41, being equal to two unit lengths of the pair of insulated wires. Thus, it is seen that as the carriage 42 is moved from its dashed line position to its solid 'line position in FIG. 1, the movement of the carriage guide sheave 41 tends to cause a two unit length slack in the pair of insulated wires 11 which is simultaneously taken up by the corresponding movement of the carriage guide sheave 46, whereby the portion of the pair of insulated wires between the carriage guide sheaves 41 and 46 is advanced longitudinally two unit lengths.

During this movement of the carriage 42 the dancer sheaves 49 of the accumulator 47 are pulled upward by the tension in the twisted pair of insulated wires 11, as shown in FIG. 1, to pay out two unit lengths of the wires to the capstan 12 so that the portion of the wires at the point 46b remains stationary and the movement of the carriage causes the desired two unit length advancement of the wires. At the same time the dancer sheaves 38 of the accumulator 33 move downward to store two unit lengths of the pair of insulated wires 11 coming from the above-mentioned source of supply.

To insure that the portion of the twisted pair of insulated wires 11 at the point 46b remains stationary as the carriage 42 is moved to the left in FIG. 1, a clamping mechanism 67 is provided between the point 46b and the accumulator 47, for clamping the twisted wires against movement during the movement of the carriage. In the illustrated embodiment of the invention, the clamping member 67 includes a roller 68 which is suitably mounted on an adjacent upright of the main frame 23, and under which the twisted wires 11 advance. Suitably mounted on the same upright of the main frame 23 below the roller 68 is a clamping member 69 which is biased downward to a released position in a suitable manner (not shown) and which is movable upward upon energization of an associated solenoid 71 to clamp the twisted wires 11 against the roller. The clamping areas of the roller 68 and the clamping member 69 may be provided with a high friction, resilient material, such as rubber, to facilitate gripping of the twisted wires 11 against movement without causing damage to the wires.

Referring to FIG. 2, it is seen that control of the reciprocation of the piston rods 54 of the double acting hydraulic cylinder 53, and thus reciprocation of the carriage 42 is accomplished by a hydraulic system including a double solenoid, pilot operated, four-way hydraulic valve 72. The hydraulic valve 72 has opposite ends of a spool thereof connected to the plungers of respective solenoids 73 and 74, and is of a type in which the spool remains in a position to which it is actuated by either of the solenoids, through hydraulic pressure on the pilot valve, even though the solenoid is then de-energized. Outlet ports of the hydraulic valve 72 are connected to opposite ends of the hydraulic cylinder 53 by hydraulic lines 76 and 77, each including an adjustable flow control valve 78 of a suitable type. An inlet port of the hydraulic valve 72 is connected to a variable volume hydraulic pump 79 by a fluid supply line 8-1, and an exhaust port of the hydraulic valve 72 is connected to a reservoir 82 by a fluid return line 83. A line 84, which is connected between the supply line 81 and the return line 83 so as to bypass the hydraulic valve 72, has an adjustable pressure relief valve 86 connected therein. The hydraulic pump 79 is driven by the capstan drive motor 13 through a belt and pulley drive which includes a pulley 87 on an extension of the motors drive shaft, whereby the pump draws hydraulic fluid from the reservoir 82 and pumps it through the hydraulic valve 72 to the hydraulic cylinder 53 in a well known manner.

Energization of the solenoid 73 moves the spool of the hydraulic valve 72 to a position in which hydraulic fluid flows into one end of the double acting hydraulic cylinder 53 through the hydraulic line 76, and from the other end of the hydraulic cylinder through the hydraulic line 77 and through the valve 72 to the reservoir 82 by the fluid return line 83. This causes movement of the piston rods 54 of the hydraulic cylinder 53 to the left, as viewed in FIGS. 1 and 2., and thus movement of the carriage 42 from its solid line position to its dashed line position in FIG. 1. The rate of movement of the carriage 42 is established by the flow control valves 78, which are set so that the speed of the carriage corresponds to the speed of advancement of the pair of insulated wires 11 by the capstan 12, whereby the portion of the wires between the points 41b and 46a associated with the carriage guide sheaves 41 and 46 has no longitudinal movement and twists of opposite hand are formed in the unit lengths of the wires between the wire support points 17a and 29a on the wire guide sheaves 17 and 29 and the wire support points 19a and 31a on the wire guide sheaves 19' and 31, as described hereinabove.

Similarly, energization of the solenoid 74 moves the spool of the hydraulic valve 72 to a position in which the flow of hydraulic fluid to and from the double acting hydraulic cylinder 53 through the hydraulic lines 76 and 77 is reversed, to cause the piston rods 54 of the hydraulic cylinder 53 to be moved to the right, as viewed in FIGS. 1 and 2. This causes movement of the carriage 42 to the left in FIG. 1, and while in the illustrated embodiment of the invention the speed of the carriage is the same as the speed of the carriage as it moves to the right in these figures, it is apparent that the hydraulic system could be suitably modified so that the carriage returns at a faster rate, so as to speed up the machines operating cycle, if so desired.

The number of twists imparted to a unit length of the pair of insulated wires 11 is a direct function of the number of revolutions of the flyer 14 during the movement of the carriage 42 to the right, as viewed in FIG. 1. Thus, by adjusting the speed of the flyer drive motor 27 the rotational speed of the flyer 14 can be set so that a twist of a desired pitch is formed in the pair of insulated wires 11. To facilitate the setting of the flyer 14 at a desired rotational speed and for the purpose of checking the rotational speed of the flyer 14 when the apparatus is in operation, a counter 88, such as the type 513F counter manufactured by the Dynapar Corporation of Gurnee, Ill., is mounted adjacent the top of the left hand upright of the main frame 23, as shown in FIG. 1. The counter 88 is controlled, in a manner to be described, so that as the flyer 14 completes each revolution during the movement of the carriage to the right in FIG. 1, a permanent magnet 89 mounted on the flyer closes a magnetic switch 91 of the counter to actuate the counter.

Referring to FIG. 3, in the illustrated embodiment of the invention an electrical control circuit for the apparatus includes a start button 92 which upon being depressed causes energization of a start relay 93. The energized start relay 93 closes a contact 93C-1 to lock operated; a contact 93C-2 to energize the capstan motor 13 and the flyer motor 27; a contact 93C-3 to condition a first control relay 94 for operation; and a contact 93C-4 to condition a second control relay 96 for operation. T 0 stop the apparatus a stop button 97 is depressed to drop out the start relay 93, thereby causing the machine to cease operating.

As noted hereinabove, the spool of the hydraulic valve 72 remains in the position to which it is actuated by either of the solenoids 73 or 74, even though the solenoid subsequently becomes de-energized. Thus, when the apparatus is placed in operation by pressing of the start button 92, as the capstan motor 13 begins driving the hydraulic pump 79 (FIG. 2) the piston rods 54- of the hydraulic cylinder 53 move to the right or to the left, as viewed in FIGS. 1 and 2, depending upon which phase of its operating cycle the apparatus was in when it was turned off, to begin reciprocation of the carriage 42. However, to help insure that the spool of the hydraulic valve 72 is in the proper position when the apparatus starts to operate, the control relays 94 and 96 may be of a suitable composite mechanical latching type which remains in position even when the electrical control circuit is de-energized.

Assuming that the apparatus is operating and that the piston rods 54- of the hydraulic cylinder 53 are moving to the right in FIG. 1, whereby the carriage 42 is being moved to the left in this figure to advance the pair of insulated wires 11 two unit lengths, as the right hand piston rod nears the end of its stroke a camming surface 54!- thereon engages and closes a first limit switch 98 suitably mounted on the support stand 59 for the accumulator 47. Referring to FIG. 3, it is seen that the closing of the limit switch 98 causes energization of the first control relay 94 to initiate the wire twisting phase of the machines operating cycle. More specifically, the energized first control relay 94 closes a contact 94C-1 to lock operated; opens a contact 94C2 to de-energize the second control relay 96; and closes a contact 94C3 to energize a third control relay 99 and a time delay relay 101.

The de-energized second control relay 96 releases a contact 96C1 in the lock-in circuit of the first control relay 94 to a closed position; releases a contact 96C-2 in its own lock-in circuit to an open position; releases a contact 96C-3 to de-energize the second hydraulic valve solenoid 74; and releases a contact 96C-4 to de-energize the solenoid 71 and thus render the wire clamping mechanism 67 inoperative.

The third control relay 99, upon being energized, closes a contact 99C-1 to energize the first hydraulic valve solenoid 73, thereby reversing the direction of movement of the hydraulic cylinder piston rods 54 and the carriage 42; closes a contact 99C-2 to energize the windings 64 of the electric brakes 61 associated with the wire guide sheaves 29, 31, 43 and 44, thereby locking these sheaves against rotation; closes a contact 99C-3 in a zero reset circuit of the counter 88; and closes a contact 99C-4 in a magnetic switch circuit of the counter. At the same time, the energized time delay relay 101 momentarily closes a contact 101C in the counter reset circuit to reset the counter 88 to zero, and then drops out so that the counter begins to count the revolutions of the flyer 14.

As the hydraulic cylinder piston rods 54 reach the end of their stroke to the left, as viewed in FIG. 1, a camming surface 541 on the left hand piston rod engages and closes a second limit switch 102. As is shown in FIG. 3, closing of the limit switch 102 causes energization of the second control relay 96 to initiate the wire advancing phase of the machines operating cycle. More specifically, the energized second control relay 96 opens its contact 96C-1 to de-energize the first control relay 94; closes its contact 96C-2 to lock operated; closes its contact 96C-3 to energize the second hydraulic valve solenoid 74, thereby reversing the direction of movement of the hydraulic cylinder piston rods 54 and the carriage 42; and closes its contact 96C-4 to energize the solenoid 71 of the wire clamping mechanism 67. The thus de-energized first control relay 94 releases its lock-in contact 94C1; releases its contact 94C2 in the lock-in circuit of the second control relay 96; and releases its contact 94C-3 to de energize the third control relay 99. The de-energized third control relay 99 releases its contact 99C-1 to de-energize the first hydraulic valve solenoid 73; releases its contact 99C-2 to de-energize the electric brakes 61 whereby the wire guide sheaves 29, 31, 43 and 44 (FIG. 1) are free to rotate as the pair of insulated wires 11 is being ad vanced; releases its contact 99C-3 in the zero reset circuit of the counter 88; and releases its contact 99C-4 in the magnetic switch circuit of the counter whereby the counter stops counting the revolutions of the flyer 14.

Operation In preparing the apparatus for a wire twisting operation, the motor 13 is adjusted to drive the capstan 12 at a desired constant wire advancing speed; the hydraulic fiow control valves 78 (FIG. 2) are set so that during the wire twisting phase of the machines operating cycle the hydraulic cylinder 53 moves the carriage 42 to the right in FIG. 1 at a speed corresponding to the wire advancing speed of the capstan, whereby the part of the pair of insulated wires 11 between the points 41b and 46a associated with the wire guide sheaves 41 and 46 on the carriage will remain stationary and reverse twists will be formed in the unit length sections of the wires between the wire support points 17a, 29a and 19a, 31a of the wire guide sheaves 17, 29 and 19, 31; and utilizing the counter 88, which indicates the number of revolutions of the flyer during the movement of the carriage 42 to the right in FIG. 1, the motor 27 is adjusted so that it rotates the flyer 14 at a speed whereby it will form a desired number of twists in the unit length sections of the wires during this movement of the carriage.

Summarizing the operation of the apparatus, it is seen from FIG. 3 that depressing of the start button 92 causes energization of the start relay 93 which then closes its contact 930-1 to lock operated; its contact 930-2 to energize the capstan motor 13 and the flyer motor 27; its contact 930-3 to condition the first control relay 94 for operation; and its contact 930-4 to condition the second control relay 96 for operation. To stop the apparatus the stop button 97 is depressed to drop out the start relay 93, whereby the machine ceases to operate.

The motor 13, upon being energized, begins to drive the capstan 12 to advance the pair of insulated wires 11 from the above-mentioned source of supply and through the apparatus from left to right, as viewed in FIG. 1. From the capstan 12 the twisted pair of insulated wires 11 passes to the right, as viewed in FIG. 1, to the abovementioned takeup. The energized motor 13 also begins to drive the hydraulic pump 79 (FIG. 2), which begins to pump fluid from the reservoir 82 to the double acting hydraulic valve 72 through the fluid supply line 81. At the same time the energized motor 27 begins to rotate the flyer 14 in the direction indicated by the arrow in FIG. 1.

Since the spool of the hydraulic valve 72 remains in the position to which it is actuated by either of the solenoids 73 or 74, as the hydraulic pump 79 delivers hydraulic fluid from the reservoir 82 to the hydraulic valve the fluid flows to the double acting hydraulic cylinder 53 to cause movement of the piston rods 54 to the right or to the left, as viewed in FIGS. 1 and 2, depending upon which phase of its operating cycle the apparatus was in when it was turned off, to begin reciprocation of the carriage 42.

Assuming that the apparatus is in the wire advancing phase of its operating cycle and that the piston rods 54 of the hydraulic cylinder 53 are moving to the right in FIG. 1, as the right hand piston rod nears the end of its stroke the camming surface 54r thereon engages and closes the first limit switch 98. Referring to FIG. 3, it is seen that the closing of the limit switch 98 causes energization of the first control relay 94 to initiate the wire twisting phase of the machines operating cycle. More specifically, the energized first control relay 94 closes its contact 940-1 to lock operated; opens its contact 940-2 to de-energize the second control relay 96; and closes its contact 940-3 to energize the third control relay 99 and the time delay relay 101.

De-energization of the second control relay 96 causes it to release its contact 960-1 in the lock-in circuit of the first control relay 94; its contact 960-2 in its own lock-in circuit; its contact 960-3 to 'de-energize the second hydraulic control valve 74; and its contact 960-4 to deenergize the solenoid 71 and thus render the wire clamping mechanism 67 inoperative.

The third control relay 99, upon being energized, closes its contact 990-1 to energize the first hydraulic valve solenoid 73, thereby reversing the direction of movement of the hydraulic cylinder piston rods 54 and the carriage 42; closes its contact 990-2 to energize the windings 64 of the electric brakes 61 associated with the wire guide sheaves 29, 31, 43 and 44, thereby causing movement of the brake shoes 63 of the electric brakes into engagement with their associated cylindrical members 62 to lock these wire guide sheaves against rotation; closes its contact 990-3 in the zero reset circuit of the counter 88; and closes its contact 990-4 in the magnetic switch circuit of the counter. At the same time, the time delay relay 101 momentarily closes its contact 101C in the counter reset circuit to reset the counter 88 to zero, and then drops out so that the counter begins to count the revolutions of the flyer 14 in response to the closing of the magnetic switch 91 by the permanent magnet 89 on the flyer.

As the carriage 42 then is moved to the right in FIG. I, from its solid line position to its dashed line position, since it is traveling at a speed corresponding to the wire advancing speed of the capstan 12 the part of the pair of insulated wires 11 between the points 41b and 46a associated with the carriage guide sheaves 41 and 46 remains stationary. Thus, desired twists of opposite hand are formed in the unit length sections of the pair of insulated wires 11 between the wire support points 17a, 29a and 19a, 31a of the sheaves 17, 29 and 19, 31.

During this movement of the carriage 42 the dancer sheaves 38 of the accumulator 33 preclude excessive tension in the pair of insulated wires 11 by moving vertically in response to an increase or decrease in tension. Further, where the rate of feed of the wires 11 from the above-mentioned source of supply is substantially constant, the dancer sheaves 38 move upward to pay out two unit lengths of the wires to the carriage sheave 41 to permit this movement of the carriage 42 to take place. At the same time the dancer sheaves 49' of the accumulator 47 move downward to take up the two unit length slack being produced in the twisted pair of insulated wires 11 by the movement of the carriage sheave 46.

As the hydraulic cylinder piston rods 54 reach the end of their stroke to the left, as viewed in FIG. 1, the cam surface 541 on the left hand piston rod engages and closes the second limit switch 102. As is shown in FIG. 3, closing of the limit switch 102 causes energization of the second control relay 96 to initiate the wire advancing phase of the machines operating cycle. More specifically, the energized second control relay 96 opens its contact 960-1 to de-energize the first control relay 94; closes its contact 960-2 to lock operated; closes its contact 960-3 to energize the second hydraulic valve solenoid 74, thereby reversing the direction of movement of the hydraulic cylinder piston rods 54 and the carriage 42; and closes its contact 960-4 to energize the solenoid 71 of the wire clamping mechanism 67, whereby the clamping member 69 is moved upward to clamp the twisted pair of insulated wires 11 against the roller 68, to preclude longitudinal movement of the portion of the wires between the point 46b and the accumulator 47.

When the first control relay 94 is de-energized, it releases its lock-in contact 940-1; its contact 940-2 in the lock-in circuit of the second control relay 96; and its contact 940-3 to de-energize the third control relay 99. The de-energized third control relay 99 then releases its contact 990-1 to de-energize the first hydraulic valve solenoid 73; its contact 990-2 to de-energize the electric brakes 61 whereby the wire guide sheaves 29, 31, 43 and 44 (FIG. 1) are free to rotate as the pair of insulated wires 11 is being advanced; its contact 990-3 in the zero reset circuit of the counter 88; and its contact 990-4 in the magnetic switch circuit of the counter whereby the counter stops counting the revolutions of the flyer 14.

As the carriage 42 then is moved to the left in FIG. 1, from its dashed-line position to its solid-line position, the part of the pair of insulated wires 11 between the points 41V: and 46b is pulled through the apparatus two unit lengths. More specifically, this movement of the carriage 42 moves an untwisted unit length of the pair of insulated wires 11 into position between the wire support points 17a and 29a adjacent the entrance to the flyer 14, (1) an untwisted unit length of the wires and (2) the twisted unit length of the wires between the wire support points 1711 and 290, into the flyer between the wire support points 17a and 19a, an untwisted unit length of the wires from the flyer into position between the wire support points 19a and 31a adjacent the exit from the flyer, and (1) a previously twisted unit length of the wires from the flyer and (2) the twisted unit length of the wires between the wire support points 19a and 31a, into a position about and beyond the wire guide sheave 31 toward the carriage.

During this advancement of the pair of insulated wires 11, any twist which was imparted to the wires by the flyer 14 as they entered the flyer is removed by the flyer as the wires exist therefrom, and thus the net twist imparted to the wires during the wire advancing phase of the machines operating cycle is zero.

During the movement of the carriage 42 to the left in FIG. 1, since the portion of the twisted pair of insulated wires 11 between the point 461; and the accumulator 47 is being held against longitudinal movement by the clamping mechanism 67, the dancer sheaves 49 of the accumulator 47 are pulled upward by the tension created in the twisted wires by the capstan 12, as shown in FIG. 1, to pay out two lengths of the twisted wires to the capstan, whereby the capstan, which is being driven at a constant speed by the motor 13, does not cause breakage of the wires.

During the operation of the apparatus the number of revolutions which the flyer 14 makes for each stroke of the carriage 42 during the wire twisting phase of the machines operating cycle readily can be determined from the counter 88, for the purpose of checking whether the flyer is rotating at the proper speed. When the rotation of the fiyer 14 has deviated from the desired speed the necessary correction readily can be made by adjusting the speed of its drive motor 27, while observing the revolutions of the flyer being recorded by the counter 88. Similarly, by adjusting the speed of the drive motor 27 the speed of the flyer, and thus the number of twists imparted to the pair of insulated wires 11, can be changed on the fly without stopping the apparatus.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. The method of forming alternate reverse twists in a strand, which comprises:

intermittently advancing the strand longitudinally so as to move at least two sections of the strand into strand twisting position with each advancement of the strand;

precluding longitudinal advancement of the part of the strand between outer limits of each two sections of the strand when the two sections of the strand are in strand twisting position; and

causing relative rotation between a portion of the strand intermediate each two sections of the strand and portions of the strand at the outer limits of the two sections of the strand when the two sections of the strand are in strand twisting position, to form reverse twists in the two sections of the strand.

2. The method of forming alternate reverse twists in a strand, as recited in claim 1, in which:

the reverse twists in each two sections of the strand are formed by rotating the portion of the strand intermediate each two sections of the strand relative to the portions of the strand at the outer limits of the two sections of the strand.

3. The method of forming alternate reverse twists in a strand, as recited in claim 1, in which:

each advancement of the strand moves at least two sections of the strand, each of which is equal to one unit length of the strand, into strand twisting position, and also moves a two unit length increment of the strand which is intermediate the two sections of the strand into a strand storing position; and

the reverse twists are formed in each two sections of the strand by causing relative rotation between each two unit length increment of the strand and the portions of the strand at the outer limits of the two sections of the strand. 4. The method of forming alternate reverse twists in a strand, which comprises:

causing continuous relative rotation between a strand engaging mechanism and strand support points spaced from the strand engaging mechanism longitudinally of the strand on respective opposite sides of the strand engaging mechanism, so that reverse twists will be formed in sections of the strand which are located between the strand support points and the strand engaging mechanism; intermittently advancing the strand longitudinally relative to the strand support points and the strand engaging mechanism so as to move at least two sections of the strand into strand twisting position between the strand support points and the strand engaging mechanism with each advancement of the strand; and precluding the advancement of the part of the strand intermediate the strand support points when each two sections of the strand are in strand twisting position between the strand support points and the strand engaging mechanism, until desired reserve twists have been formed in the two sections of the strand by the relative rotation between the strand support points and the strand engaging mechanism. 5. Apparatus for forming alternate reverse twists in a strand, which comprises:

first and second strand engaging means spaced apart longitudinally of the strand, each of said first and second strand engaging means being engageable with a portion of the strand so as to preclude any substantial rotation of the strand portion about the longitudinal axis of the strand relative to said strand engaging means; intermediate strand engaging means located between said first and second strand engaging means, said intermediate strand engaging means also being engageable with a portion of the strand so as to preclude any substantial rotation of the strand portion about the longitudinal axis of the strand relative to said intermediate strand engaging means; means for intermittently advancing the strand longitudinally relative to said several strand engaging means, to move two sections of the strand into strand twisting position between said intermediate strand engaging means and respective ones of said first and second strand engaging means with each advancement of the strand; means for precluding advancement of the part of the strand between said first and second strand engaging means after each two sections of the strand have been advanced by said strand advancing means into strand twisting position between said intermediate strand engaging means and said first and second strand engaging means; and means for causing relative rotation between said intermediate strand engaging means and said first and second strand engaging means, to form reverse twists in each two sections of the strand when the sections are in strand twisting position between said intermediate strand engaging means and said first and second strand engaging means. 6. Apparatus for forming alternate reverse twists in a strand, as recited in claim 5, in which:

said means for causing relative rotation between said intermediate strand engaging means and said first and second strand engaging means rotates said intermediate strand cngaging means continuously relative to said first and second strand engaging means.

3,402,544 13 14 7. Apparatus for forming alternate reverse twists in and said first and second strand engaging means by a strand, as recited in claim 5, in which: the relative rotation therebetween;

said first and second strand engaging means are romeans for moving said reciprocable means and said tatable members; and

said means for precluding advancement of the part of the strand between said first and second strand engaging means includes means for precluding rotation of said rotatable members during the forming of the guide members thereof in a reverse direction so as to move two sections of the strand into strand twisting position between said intermediate strand engaging means and said first and second strand engaging means;

reverse twists in the strand. 8. Apparatus for forming alternate reverse twists in a strand, as recited in claim 5, in which:

said intermediate strand engaging means has a strand storing capacity of two unit lengths of the strand; guide members thereof; and each of said first and second strand engaging ns means for rendering said second moving means operais spaced one unit length of the strand from id 15 tive when desired reverse twists have been formed in intermediate strand engaging means; and the sections of the strand between said intermediate said strand advancing means intermittently advances Strand engaging means and Said first and Second the strand longitudinally relative to said several Strand engaging meansstrand engaging means in successive two unit length APPaFatuS for forming alternate reverse twists in increments. a strand, as recited in claim 9, which further comprises: 9. Apparatus for forming alternate reverse twists in a fi t Strand accumulator through Which the Strand a strand, as recited in claim 5, in which said means for Passes Prior to traveling about Said first guide intermittently advancing the strand longitudinally comof Said reciprocable means; and prises: a second strand accumulator through which the strand reciprocable means including a first guide member passes to said constant speed strand advancing means means for rendering said first mentioned moving means operative when two sections of the strand have been advanced into strand twisting position by the reverse movement of said reciprocable means and said about which the strand travels prior to passing to said first strand engaging means and said intermediate strand engaging means, and also including a second guide member about which the strand travels after traveling about said second guide member of said reciprocable means, each of said first and second strand accumulators taking up and paying out the strand in response to variations in tension in the strand as said recipricable means is reciprocated by after passing from said intermediate strand engaging said first and second moving means.

means and said second strand engaging means;

means driven at a substantially constant speed for advancing the strand about said guide members and relative to said several strand engaging means;

means for moving said reciprocable means and said References Cited UNITED STATES PATENTS b h f t f 3,320,350 5/1967 Corrall et a1. 57-64 XR gui e mem ers t ereo in one tree mm at a ra e 0 3,367,097 2/1968 Menasoff 57 34 speed corresponding to the strand advancing speed of said constant speed strand advancing means so FOREIGN PATENTS that the part of the strand between said first and sec- 1,470,269 1/1967 France.

ond strand engaging means remains substantially stationary and reverse twists are formed in the sections of the strand which are in strand twisting position between said intermediate strand engaging means FRANK I. COHEN, Primary Examiner.

W. H. SCHROEDER, Assistant Examiner.

U.S. DEPARTMENT OF COMMERCE PATENT OFFICE Washington, D.C. 20231 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,402,544 September 24, 1968 William R. Michael et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 42, "interwisting" should read intertwist ing line 59, "separate" should read separate Column 2, line 43, after "strand", first occurrence, insert support points when each two sections of the strand Column 14, line 30, "recipricable" should read reciprocable Signed and sealed this 3rd day of March 1970.

(SEAL) Attest:

WILLIAM E. SCHUYLER, JR.

Commissioner of Patents Edward M. Fletcher, Jr.

Attesting Officer 

